Process for the production of gasoline through thermal and catalytic cracking



July 21, 1959 F. KuNREuTHEr-z` ETAT. 2,895,899

PROCESS FOR THE PRODUCTION OF GASOLINE THROUGH THERMAL AND CATALYTIO CRAOKING Julyl 21, 1959 Filed NOV. 5, 1954 F. KUNREUTHl-:R ETAL 2,895,899 PRocEss Foa THE: PRODUCTION oF GAsoLTNE THROUGH THERMAL AND CATALYTTC CRACKING 2 Sheets-Sheet 2 FIG. 4

STRIPPING STEAM I'REGENERATOR FIG. 2

INVENTORS REGENERATOR) WILLIAM K. MEERBOTT AIR OR STEAM FREDERICK KUNREUTHER `TI-lElR ATTORNEY 2,895,899 Patented July 21, 1959 Y tice IROCESS FOR THE PRODUCTION OF GASOLINE 'IOUGH THERMAL AND CATALYTIC CRACK- Frederick Kunreuther and William K. Meerbott, Houston, Tex., assignors to Shell Development Company, New York, N.Y., a corporation of Delaware Application November 5, 1954, Serial No. 467,064 6 Claims. (Cl. 208-70) This invention relates to an improved method for converting hydrocarbon oils boiling above the gasoline boiling range into gasoline of good quality in good yield. A specific aspect of the invention relates to the catalytic treatment of thermally cracked gasoline stocks, including fractions thereof.

It is generally recognized that the process known as catalytic cracking produces gasoline of better quality than thermal cracking and other comparable processes. Consequently it is the desire and practice to catalytically crack as much of the available oil as possible. Certain feed stocks are, however, not amenable to catalytic cracking and it is the practice to convert such stocks, e.g., residues, catalytically cracked gas oils, etc., by thermal cracking methods, e.g., Dubbs cracking, delayed coking, uid

coking, etc. This produces a good olenic gasoline but the gasoline is distinctly inferior to that produced by catalytic cracking.

It is known that thermally cracked gasolines may be improved in quality by subsequently treating them with cracking catalysts and this operation was carried out during the late war to produce aviation base stock (which contains very little olens). The process was discontinued, however, as soon as the exceptional demand for aviation base stock ceased to exist, due to the fact that this subsequent treatment involved a considerable loss of gasoline. These losses resulted primarily from cracking of the gasoline to light gases and to some extent by polymerization or condensation reactions producing higher boiling products. Various attempts vhave been made to curtail the losses due to cracking through the use of mild treating conditions and particularly through the use of partially deactivated catalysts, e.g., catalyst which has been partially spent in a conventional catalytic cracking operation. In spite of these expedients, the loss of gasoline remained sufliciently high that, as far as we are aware, the process finds no commercial application.

We now have found that part of the reason for previous failures to improve the process lies in the fact that previous attempts sought to apply the process in apparatus and process ows which could not provide the special conditions which we now find are required. These conditions briefly stated are (l) the avoidance of contact of the thermally cracked gasoline with so-called dense phase or fluidized cracking catalyst, (2) the use of much lower catalyst-to-oil ratios than normally applied in this and related processes, and (3) a very short contact time between about 0.2 and 0.6 second. In addition to these conditions it is most advantageous to employ freshly regenerated catalyst of full activity (which then allows a minimum contact time) rather than a previously used and partially spent catalyst. Also, in order to allow a minimum contact time, it is most advantageous to employ temperatures of at least 950 F. and preferably temperatures from about 970 to 1070 F. Y

It will be appreciated that commercial size apparatus cannot afford these conditions unless specially designed t provide them. For example, the velocity of catalyst suspensions in lines must in practice be held below about feet per second (in normal design the velocity is usually limited to about 30 feet per second) because of erosion difliculties. A riser line, which in a commercial unit may be anywhere from 50 to 150 feet long, therefore cannot afford a suitable contact time. Also, for example, to obtain temperatures above 1000 F., it is the custom to preheat the feed vapors and supply the additional heat required with the hot catalyst. The thermal gasoline can be preheated to temperatures of around 1000 F. but this would defeat the purpose since at such temperatures thermal cracking is appreciable and causes the very losses that it is sought to avoid.

These difficulties are avoided in the process of the invention through the use of special arrangements of apparatus and process ows.

The process of the invention will be further described with reference to the accompanying drawings in which suitable apparatus and the main flows are shown semidiagramtnatically and in which:

Figure l illustrates one suitable ilow diagram;

Figure 2 illustrates in some more detail the main reaction and regeneration apparatus of the flow diagram of Figure l;

Figure 3 illustrates a different arrangement of the reac- 'tion and regeneration apparatus such as may be used, for

instance, in the flow diagram of Figure 1;

Figure 4 is a somewhat enlarged detail of part of the reactor of Figure 3 modied to incorporate stripping of the used catalyst.

It will be appreciated that certain parts of the apparatus, eg., cyclone separators, grids, furnaces, aud the like, are illustrated in stylized or symbolic form and that, for the sake of clearness, no attempt has been made to illustrate Various conventional minor appurtenances such as control mechanisms, provision for reux, reboilers, and the like.

In describing the apparatus and flows, the broader and preferred operating conditions are given. The figures shown in parenthesis refer to a specific example of the operation.

The flow shown in Figure l includes the thermal cracking step as well as the rst step in the product recovery. It will be understood that either of these steps may be carried out somewhat differently. Referring to Figure 1, a hydrocarbon oil boiling essentially above the gasoline boiling range, and preferably a residue or gas oil fraction which is a poor feed for catalytic cracking, is introduced by line 1 and pump 2 to the coils of a cracking furnace 3 wherein it is heated to cracking temperatures in the conventional manner. The material is then passed to a cracking and/or separating chamber 4. Cracked vapors are removed overhead by line 5 to a fractionator 6 whereas residue is removed from the bottom. This residue may be removed from the system or recycled to the cracking furnace in whole or in part as needed. In conventional thermal cracking, fractionating column 6 would be oper? ated to remove as overhead product a thermally cracked gasoline having an end point somewhat lower than the usual gasoline end point. Thus, the end point is normally around 3504360 F. It is normal to operate in this manner since the material boiling above about 350 F. in thermal gasoline is of particularly poor quality and its inclusion tends to degrade the gasoline. In the present process, the thermal gasoline may be cut to the usual end point. However, it is found that when the present process is employed the end point may be raised considerably, e.g., to 415 F., thereby considerably increasing the yield of gasoline without degradation of its quality. The higher boiling bottom product from fractionating column 6 may be withdrawn from the system or recycled through the thermal cracking step. As will be later explained it may,

E however, be advantageously utilized as a coke former in the subsequent operation in which case it is in whole or in part passed to line 7.

The thermal gasoline removed overhead from fractionating column 6,may be passed directly to the heater 8 and thence to the catalytic treatment, but it isk preferably topped in topping column 9. Column 9 may be operated merely to remove normally gaseous products, but it is preferably operated to remove products up,Y through C4 and more preferably up through C5. In the lattercase, the depentfanized bottom product may have an A STM initial boiling point of, for example,4 160- l70, F.

In the specific example the depentanized thermalgasoline has the following properties:

API gravity 60.@ F. 55.4

ASTM distillation, F.:

IBP 167 10% 204.A 20% 216 30% 229 40% 241 50% 254 60% 26'7' 70% 274 80% 296 90% 317.V 95% 334 EP 358 F-l octane number 174.3

1 Debutanized.

It is preferably superheated to the highest temperature possible without any appreciable cracking, but superheating tolower temperatures is possible in some cases as will; be clear from the further dcription` of the process. Thus, ternperaturesof from about 625 F. up to the maxi,-y mum. which can be obtained without appreciable cracking may be used, This latter temperature depends. con,- siderably upon the designl of the furnace, the character of the thermal gasoline and the amount of cracking which;` may he tolerated. Regarding the latter, the superheating should be curtailed such that notA more than. about 0.5% f tbs ghsblihs is, sshvbrted. t0 products boiling. hillside of the gasoline range. y

Referring to Figures lk andY 2 wherein like p arts are indicated by the same reference numbers, the catalytic section comprises a catalyst regenerator 11k which may be of any suitable designY and which operates to burn carbonaceous deposits fr-,ornv the spent catalyst with air or other oxidizing gas at a temperature between, about 1090 F. and 1200 F., (1125 F.) Hot regenerated catalyst is, withdrawn from. the regenerator by standpipe 12 at a rate controlled by valve 13,

The preferredl catalyst isthe synthetic silica-alumina cracking catalystcommercially use d in: the uidized catalyst catalytic cracking process butany other nely divided solid cracking catalyst such, for instance, as', certain treated clays (so-called natural catalyst), HF treated alumina, alumina-boda, aluminumA lluoride-aluminum,v phosphate, siliafmagnesia, silicafmagnesiafalumina silica;V zirconia, and the like, may be used. This class of` catalyst is designated clay-type cracking catalyst., The claytypev crackingl catalysts are characterized byv having a highly microporous structure affording a large available, surface, by having highly acid centers whichpromote the cracking of hydrocarbons, by the absence offany appreciableamounts of active forms of heavy metal corn-4 pounds, of the.hydrogenation-dehydrogenation type (e.g. Fe, Cr, Ni, Co, Mn, Mo, Cu, V.) which cause,excessive,V coke formation, and by their ability to withstand tem-` peratures of at least; about l100 F. without appreciable t sintering, The, catalyst may be1 ground to pass a, U S:; standard 100 mesh sieve or maybe produced in the form,

of microspheroidalparticles. InA the'specic example,v the.

5 bilisgsraslsedarid; further; sarbnhiaes thecatalysh Shf.- t

catalyst is an equilibrium synthetic silica-alumina crackills. Catall# having. the fqllowihg. inspection data:

Surface area m.2/g 102 Pore volume cc./g 0.260 Average pore radius A 54 A1203 percent-- Ca. 14 Fe ..do 0.11 V do 0.0034 Cu -do.. 0.0007 Cr dn 0.0019 Ni .c ,d0-,f 0-0018 50 microns 10.0 120 microns 15.0

As pointed-out above, itis found that one of the requirements for ellicient conversion without appreciable cracking is the use of a catalyst-to-oil ratio which is considerably below those normally used in related processes. Til? calalytsl-lQ-Qil .ral-io is,A the ratio Qi. they weight of catalys.,t t0- tllf Weight: Qi thermally: crackedr gsshlihe continu-A Thasllpsrbbalbd varlhrsbf the thermally crac-.kedsaso lille?. (840? El); are introdllssd' into line l5 by line 17.1

As previously pointed out, it is essential in; the present.

PIQCCS that-lila- Varlbhs: 0 tbs: thermally cracked gasoline. beY contacted, withk theV dispersedy catalyst, but not withsQ-callcd rieuse; catalyst phase-4 This requires that the `yelrlsilyY 0I ille susreshsirzrifY be, maintained, at all times suflitgieirtly highto.. maintain the, catalystA particles in; free` shspehslbrl. in tbs. vapbrs and prevent. them fromA settling;

intQ a shfcallbduidizesl traendo-Halli@ phasesuch asis` the sass inf lbs.- regsrieratori. The,I minimum- 'vslceity dbf-v P-Qllsls'uplil'ths' Size distribution and: rangs. of.- the: Catalyst aarlsles and tbbrsarryihsgpqwsr O f the vapor; nurturev but, around 3.0 feet per sssqhd'in lirisso this type. Ou1 the other hand, thefve locity cannot., for practicallreasans, erase@ about isst per second if the line.- contains a, bendor about feet per, second ifthe` linef contains,

119 brad.- 1h4 thsiparlicularexarhhle, the velocity at thel irlsllleibszhsssssary short Contact time. the. shperheatsd labors cfr-tbs, illsrrhally bracketi-` gasoliricare ihtraduced..

ihtoY thesteamvsatalyslsusnshsihn: inhibe. line at intr/rmsrllate-.pqint Irlthe; particular example; the point of ibllbdllslibhis abba@ 12; fest frein the and,A thhsgil/inav a Contact tingteol` alittle qvcrOfZ second?, Underthese cOnditigrls ahdvwbshfOperatihsfwithpa tsiriprratiira` of; 1005 F l abili@ exil 0f ilus: 1.5,.. the thermalfgasclinef is; upgraded: whbreastbs I?,rollilsztihrlv of; C4 hydrocarbons. (w-lilchrhv malrlsih. fllsvgaqlins) is: less th,ar1 ,2% and the; loss: t0y lowerbbilihghrhslustszis; only abol1h1,=%, or less., 011. the other hand, the-loss i0.4 colse; is chl about 0.2i to,- 0,4%. TheA p ,ercent-agey oft coke based; ou the,y catalystY is,

about 0.01%,

Catalyst-containingzonly 0,05%. cokeycannot supply sufficient, heat: in the, regeneration tof milk? the process self-l pporting, in. this respect. The. catalyst., separated hy'ihsssnaraios 1li-is still very batfaildbiaily activaof, vessel-,18s A' hydrqsarbbn; bil; which ybilsbsssritislly above the gasoline boiling,y range;is,injectel, into,this bedg bxlihsf 1 2 and thedislr-ihlltbrfsohneted: thereto This il by line. mail@ the Aresulting disnsrsibn, is passed' escasos cient oil is thus injected to afford the mentioned regeneration temperature. While any high boiling hydrocarbon oil may be used for this purpose, it is advantageous to employ oil from the bottom of the topping column 6 introduced by line 7 as previously described. Also there is generally a small carry-over of so-called catalyst nes with the vapor product in spite lof the use of efficient cyclone separators. This catalyst collects in the bottom product of the production fractionator 20. This resulting slurry may advantageously be used in place of, or in addition to, other oils. If a secondary product fractionator 21 is used instead of side strippers for intermediate products attached to column 2t), the bottom product of the secondary fractionator may also be so used. Part of the slurry oil may also advantageously be recycled to the thermal cracking via line 22.

The carbonized catalyst from vessel 18 is withdrawn continuously via standpipe 23 and passed with air via line 24 back to the regenerator.

The hot regenerated catalyst continuously Withdrawn from the regenerator via standpipe 12, being in a fluidized state, contains appreciable amounts of gas and the gas normally contains a small amount, e.g., 0.5% of oxygen. In a plant of commercial size, the oxygen so introduced into line may be sucient to burn many barrels of the thermally cracked gasoline per day. In order to avoid loss of this valuable material, a small amount of oil of low value may be introdced with the steam via line 25. The amount of oil so added in the process illustrated should be held to the minimum required to scavenge the oxygen, but in some other cases, as will be explained, large amounts can be employed.

While in the process just described with reference to Figure l, a small amount of oil may be added to scavenge the oxygen and some small amount of oil is cracked to increase the concentration of the coke on the catalyst, it is to be understood that the process is not a catalytic cracking process as this term is generally understood in the industry. The amount of catalyst Vsupplied via line 12 is only suliicient to provide the prescribed low catalyst-to-oil ratio with respect to the thermal gasoline and this amount would be totally insufficient to supply the requirements of a catalytic cracking process.

On the other hand, it is frequently desirable to integrate the process with catalytic cracking and this can be done by utilizing the principles set forth above While affording means for supplying the required amount of catalyst for the cracking step. Thus, the regenerator and reactor system illustrated in Figure 3 may be substituted. Referring to Figure 3, it can be seen that by raising the regenerator and supplying a suitable inclined standpipe 31 a major portion of freshly regenerated catalyst may be fed to the reactor by gravity. This then allows a reactor with a dished bottom (as distinguished from the usual conical bottom) to be employed and this in turn allows a straight riser 32 of suciently short length to be applied for the treatment of thermally cracked gasoline. In this case, the relatively small amount of hot freshly regenerated catalyst required for treating the thermally cracked gasoline is introduced into the riser line 32 via inclined standpipe 33 and valve 34. As previously pointed out, with a straight vertical line such as 32 high linear velocities may be safely employed.A Due to this fact and the fact that a relatively short tube may be employed in this arrangement, the catalyst introduced via line 33 and valve 34 may be dispersed directly with the superheated vapors of the thermally cracked gasoline introduced via line 35 instead of using steam for this purpose. It is, however, generally preferable to disperse the catalyst in steam or steam containing a scavenging amount of less valuable hydrocarbon material, e.g., natural gas, and introduce the superheating vapors of the thermally cracked gasoline at an intermediate point via 'line 36. When using an apparatus such as illustrated in Figure 3, a catalytic cracking operation may be simulf 6 taneously carried out by introducing the oil to be cracked via line 37.

When effecting conventional catalytic cracking in addition to the treatment of thermally cracked gasoline, it

is generally desirable to include additional facilities for stripping the spent catalyst before it is regenerated. In

the apparatus illustrated in Figure 3, the catalyst isstripped sufficiently to decrease the regeneration load by the steam introduced via line 38 and used toA transport the catalyst spent into the regenerator. However, the stripped material is lost with the ue gas. In the modiication of the reactor illustrated in Figure 4, additional stripping with recovery of the main stripped material is effected in the depending stripping zone 41. This zone, it will be observed, is oifset in such a manner as to allow riser line 32 to be retained short, thereby affording the required short holding .time without requiring an excessive linear velocity.

In conventional catalytic cracking, the vaporous product is passed to a iirst fractionating column wherein it is de-superheated and fractionated to separate as an overhead product all of the gasoline and lighter boiling products. This fraction is then cooled to condense the gaso line and passed to a separator to separate the condensed liquid from the uncondensed vapors. The vapors are compressed, e.g., to 300 p.s.i.g., and the compressed vapors and the liquid are passed to a rectified absorber tower to separate so-called dry gas. The liquid is then passed to a debutanizer column to separate mainly Ca-C., hydrocarbons and produce so-called debutanized gasoline which is then given such further treatment as necessary, eg., extraction of mercaptans, and blended to produce the finished gasoline. The compression of the cracked gases required for eicient separation and recovery by this or related process schemes is a major operating cost in catalytic cracking and many catalytic cracking plants are limited by the compression capacity at this point. When the treatment of thermally cracked gasoline is integrated with a catalytic cracking operation, the treated thermally cracked gasoline may be combined with the n catalytically cracked gasoline and the mixture passed to a single recovery system such as described. However, when using the treating method of the invention, the increased load on the product recovery system can be avoided since, when properly applied, there is practically no gas produced, e.g., 0.1%, and the treated thermally cracked gasoline does not contain sucient C4 hydrocarbons to require stabilization.

This has distinct advantages over and above the decreased load on the product recovery system. Thus, the treated thermally cracked gasoline, if withdrawn separately from the catalytically cracked product, may bypass the usual product fractionation system. The thermally cracked product may therefore be withdrawn from the treater at a lower pressure than that of the catalytically cracked vapors. This then allows catalyst to be transferred from the regenerator to the gasoline treating tube with a much lower head of catalyst, i.e., a much shorter standpipe. This, in turn, allows a much shorter reaction tube to be used. As previously pointed out, this is advantageous as it allows the desirable short contact times to be obtained in commercial operation without excessive linear velocities of the dilute catalyst suspension.

One of the features of the present process (in which the thermally cracked gasoline is contacted with dispersed catalyst but contact with so-called dense phase catalyst is avoided) is that the process affects a rapid shift of the double bond in alpha olens to internal positions thereby increasing the octane number while, at the same time, depreciation of the octane number through saturation of olens and destruction to gas and coke are minimized. These latter two reactions take place to significant extents in the conventional treating process and y in all such cases where the thermal gasoline is contacted with fluidized catalyst (pseudo liquid).

While a smllamount of crackingV of the thermally cracked gasoline talresipl'ace' inI the present process, the cracked products Inspection ofJ the properties of"th'e.products obtained: bytheproc'ess show a 20 to'35% reduction in sulfur. andL4 m40-50%" reduction ofthe conjugated"dioleiins present` The only change inthe boilingirange in" the charge: was a' smallA increase in' the' end ,pointf of thev product;

For example; when treating a'depentanized charge having:

a point'of334 F; andiinal boilingpoint of358". F5, thel 95% point isincre'asedto about 342 F. and ithe`final boiling point` to`about 410 F. The rela;

tive performance ofA the untreatedvand treated thermal' gasolmem a renery'pool` gasoline was A.also investigated:V

Calculation'of the'blending octane numbers of the de'- pentanized charge'and productshowszthatjthe described process affords-an F-loctane increase ofgfrom 2;5 to

6.0 units unleaded and from 3.0 to 6` units at the 2.0

mended aiord the-greatest improvement in the F-1rating oft the product. Unblended F-l octane numbers increased'from 1.7 to4.3l unitsV unleaded and from 2.6 to

4.0--units at 2.0 cc. of TEL upon'increase of the temperature by 122 F.

Lead susceptibilitieswere-determinedfor the unblended and pool blended motor ratings.v The leadsusceptbilities for the treated vproduct are inl general equal to or slightly better than the'untreated charge. This is a de'- cidedadvantage over the conventional treatments of thermal` gasoline. When thermal gasoline is treated with a luidized'v bed of catalyst, the lead susceptibility of the product` is lower than that' ofthe charge; This is also the case When'operating with a fixed bed of catalyst as indicated: by the trend* towardlower octane number irnprovement as the concentration of TEL in the product is increased.

The' thermal gasoline treated by the 'described processv is a` product which diiers markedly from that obtained by conventional treatmentA of thermal gasoline. Thus, whereas the olefinV disappearance in conventional: treatment may be typically 48%, the olefin disappearance in the present processeis normally of the order of -4 to 10%. On the other'hand, the saturates in the feed are reduced-somewhat by" the present process whereas they are normally increased `in'the conventional treating methods. The decrease in saturatescontent canl be accountedv fo'r primarily* by increase inthe aromatic content.

Infra red olefin type analyses of the olefin concentrates separatedchromatographically from the product treated according to the invention showa marked change from alpha-type double bondsinthe charge to product olefins with internal double bonds. Approximately 60 to 80% of the alpha olefins areV convertedto beta-type olens, andpart to types not detectable by the infra red method, e.g., cyclic olens, aromatics with alkeneV side chains, etc. The low catalyst-to-oilratios specified in the present process are particularly conducive tothe largest production of desirable type olefins with minimum disappearance ofoleiinsdue to saturation. Thus,- both the catalyst-to-oilratio, the short contact time, the high temperature, and the avoidance of contacting the gasoline vapors With= adensecatalyst bed` allV play important roles in determining-the direction of the reaction of the-alpha olefins. There is some evidence, although it is not:v conclusive, thatsome skeletal isomerizationmay-also occur inthe process.- However, such skeletalisomerization does not appear to play any significant role. On the other'hand, in' the conventional operation with a fluidized catalyst bed, ithas been determined that considerable' skeletalA isomerization is essential to counteractthe lossin' octanenumber which' would otherwise result fromme-saturation ofthe normal olefi'ns:

A olefinic thermalY gasoline; producing'a dispersion of finelylv divided freshlyregenerated' cracking-catalyst in'superheated steamlandpassingA said dispersionas a` rapidly;V movingfree suspension througha narrow confined ver-A tical'pathto'av separating zone, injecting said vaporized and superheated olefinic gasoline vapors intosaid con: fined path near the top thereofLat a point suiciently close to' said separating'zone, that the residence time of the said' gasoline vapors'in said path is between 0.2 and' 0.6: second, maintaining the temperature of the said vapors in said path between 950 F. and 1l00 F. and regulating the. quantity` ofisaid'catalyst dispersed in said steam such .that the weightratiofof catalyst to olenic gasoline is between' about2 and 8.

2. Process for the. production of high octane olefinic gasoline which. comprises thermally cracking a hydrocarbon oil, separatingfrom the cracked product an ole'- finic thermalr gasoline, vaporizing and superheating said olefinic thermal gasoline, producing a dispersion of finely divided"fre'sh.ly` regenerated. cracking catalyst in superheated steam andpassingV said dispersion as a rapidly moving free suspension through. a narrow confined path' to' a separating'zone, injecting said'vaporized and superheatediolefinic` gasoline vapors into said confined pathl near the top; thereof ata point sufficiently closeV to said separating'zone that the residence time of the said gaso-Y line vapors in said path isbetwcen' 0:2 and 0.6 second,- maintainingv theK temperature of the said vapors in said-v path between` 950' F. and 1100* FL, regulating the quantityv of saidicatalyst dispersed' in said steam such that theweight'ratioofcatalystto'olefinic gasoline is betweenY about 2'and 8, separating the-catalyst fromA the mixture' of steam' and" gasoline vapors in said separating zone, collecting the'separated catalyst asa dense fluidized bed, injecting a hydrocarbon' oil in saiduidized bed to crack the sameand'deposit carbonaceous deposits onsaid catalyst', and' then'regenerating' the carbonized catalyst by: burning Ythe carbonaceous deposits therefrom in a separate regeneratiorrzone thereby to produce the afore-A mentioned 'hot' freshly regenerated catalyst.

3'. Process for the production of'high octane olefinic gasoline which comprises AthermallyA cracking a hydrocarbon oil, separating' from` the cracked product an olefinic thermal, gasoline,l vaporizing and superheating said olefinicthermal gasoline, producing a dispersion of finely dividedhotfreshly regenerated catalyst in superheated steam containing asmall amount of hydrocarbon oil other-than-gasoline suicient to react with the oxygen normally carried with' the hot regenerated catalyst, pass-1V ing said mixture as a rapidly moving free suspension through a narrow Vconfined path to a separating zone, injecting said' vaporizedl and-superheated olefinic gasoline vapors' into saidV confined path near the top thereof at a point suciently close toV said` separating zone that the residence time` of the saidL gasoline vapors in said` path is;between0.2 and0.6 second, maintaining the ternperature-of the saidvapors in said path between 950 F. and l F., and regulating the quantity of said catalyst dispersed in'saidsteam suchthat the weight ratio.` of'catalyst to oleiinic gasoline is between about 2 and 8.

4. lna'process forv the` production of gasolineinvolving the thermalcracking-'ora hydrocarbon oil boiling. essentially above the gasolinerange'to produce athermal ly cracked gasoline and the separate production of. catalytically crackedv gasolineby the catalytic cracking` of-'the hydrocarbon oil boiling-essentially above the gasoline-boiling'rangeethrough thev use of a finely divided.. cracking'. catalyst whichiscontinuously regenerated in'A aseparatel regeneration` zonenby burningcarbonaceous:4 deposits therefrom, theimprovement which comprises` Fmi continuously withdrawing hot freshly regenerated catalyst from said regeneration zone, suspending the said Withdrawn hot freshly regenerated catalyst in superheated steam and transporting the resulting suspension up through an elongated tubular reaction zone at a temperature between 950 F. and 1100 F. to a catalyst disengaging zone at sucient velocity to prevent separation of a dense catalyst phase, injecting into said suspension in said reaction zone preheated vapors of said thermally cracked gasoline at a point along the length of said tubular reaction zone near the top 4thereof sufficiently close to said catalyst disengaging zone that the residence time of the gasoline vapors in said reaction zone is between about 0.2 and 0.6 second, and adjusting the rate of said withdrawal of said freshly regenerated catalyst from said regeneration zone such that the weight ratio of `catalyst to thermally cracked gasoline in said reaction zone is between 2 and 8.

5. In a process for the production of gasoline involving the thermal cracking of a hydrocarbon oil boiling essentially above the gasoline boiling range |to produce an olelinic cracked gasoline and the separate production of catalytically cracked gasoline by the catalytic cracking of a hydrocarbon oil boiling essentially above the gasoline boiling range through the use of a nely divded cracking catalyst which is continuously regenerated by burning carbonaceous deposits therefrom in a separate regeneration zone, the improvement which comprises, continuously withdrawing hot freshly regenerated catalyst from said regeneration zone and passing the same into a fiuidized bed of said catalyst in a separate cracking zone, injecting the said hydrocarbon oil to be catalytically cracked into said bed of fluidized catalyst in said cracking zone, maintaining a catalyst disengaging zone above the level of said fluidized bed in said cracking zone, withdrawing vapors of catalytically cracked gasoline substantially free of catalyst from said disengaging zone, separately withdrawing continuously a second portion of hot freshly regenerated catalyst as a confined stream from said regeneration zone, dispersing said second portion of hot freshly regenerated catalyst in superheated vapors of said thermally cracked gasoline the weight ratio of catalyst to gasoline in said dispersion being -betWeen 2 and 8, passing the resulting dispersion as a confined stream up through said fluidized bed and discharging the dispersion into the said disengaging zone above said fluidized bed, maintaining the temperature of said dispersion in said confined stream between 950 F. and 1l00 F., maintaining the velocity of said dispersion in said conned stream sufficiently high to prevent settling of the dispersed catalyst and sulciently high that the residence time in said confined stream is between 0.2 and 0.6 second, withdrawing from said disengaging zone vapors of the thermally cracked gasoline commingled with the said vapors of the catalytically cracked gasoline, withdrawing spent cracking catalyst from said fluidized bed and passing the same into said regeneration zone.

6. The process claimed in claim 5 in which the said second portion of hot freshly regenerated catalyst withdrawn from said regeneration zone is iirst dispersed in superheated steam and the said superheated vapors of the thermally cracked gasoline are introduced into Ithe resulting dispersion.

References Cited in the le of this patent UNITED STATES PATENTS 2,259,486 Carpenter Oct. 2l, 1941 2,356,697 Rial Aug. 22, 1944 2,395,274 Hillyer et al. Feb. 19, 1946 2,397,639 Berg et al. Apr. 2, 1946 2,410,316 Thomas Oct. 29, 1946 2,410,908 Thiele et al Nov. 12, 1946 2,663,675 Ewell Dec. 22, 1953 2,766,184 Blanding Oct. 9, 1956 2,813,916 Boston Nov. 19, 1957 

1. PROCESS FOR THE PRODUCTION OF HIGH OCTANE OLEFINIC GASOLINE WHICH COMPRISES THERMALLY CRACKING A HYDROCARBON OIL, SEPARATING FROM THE CRACKED PRODUCT AN OLEFINIC THERMAL GASOLINE, VALORIZING AND SUPERHEATING SAID OLEFINIC THERMAL GASOLINE, PRODUCING A DISPERSION OF FINELY DIVIDED FRESHLY REGENERATED CRACKING CATALYST IN SUPERHEATED STEAM AND PASSING SAID DISPERSION AS A RAPIDLY MOVING FREE SUSPENSION THROUGH A NARROW CONFINED VERTICAL PATH TO A SEPARATING ZONE, INJECTING SAID VAPORIZED AND SUPERHEATED OLEFINIC GASOLINE VAPORS INTO SAID CONFINED PATH NEAR THE TOP THEREOF AT A POINT SUFFICIENTLY CLOSE TO SAID SEPARATING ZONE THAT THE RESIDENCE TIME OF THE SAID GASOLINE VAPORS IN SAID PATH IS BETWEEN 0.2 AND 0.6 SECOND, MAINTAINING THE TEMPERATURE OF THE SAID VAPORS IN SAID PATH BETWEEN 950* ;. AND 1100* F. AND REGULATING THE QUANTITY OF SAID CATALYST DISPERSED IN SAID STEAM SUCH THAT THE WEIGHT RATIO OF CATALYST TO OLEFINIC GASOLINE IS BETWEEN ABOUT 2 AND
 8. 